High intensity LEDs are becoming more popular as light sources for traffic lights, automobile interior and exterior lighting, signboards, and other applications. The light output of a silicon LED chip is not only a function of the chip size and the process, but also a function of the junction temperature of the LED. By keeping the junction temperature low, LEDs can be driven with twice or three times as much current and, thus, generate twice or three times the light output while still extending the life of the LEDs. Currently, however, there is no instrument that can drive a LED at a given current and measure the corresponding junction temperature rise at the same time.
There is a desire for an instrument that can measure a relationship between LED junction temperature and drive current.